1. Field
The disclosed aspects relate generally to communications between devices and specifically to methods and systems for improving remote near field communication (NFC) device detection through use of an oscillator circuit connected to an NFC antenna and matching network.
2. Background
Advances in technology have resulted in smaller and more powerful personal computing devices. For example, there currently exist a variety of portable personal computing devices, including wireless computing devices, such as portable wireless telephones, personal digital assistants (PDAs) and paging devices that are each small, lightweight, and can be easily carried by users. More specifically, the portable wireless telephones, for example, further include cellular telephones that communicate voice and data packets over wireless networks. Many such cellular telephones are manufactured with ever increasing computing capabilities, and as such, are becoming tantamount to small personal computers and hand-held PDAs. Further, such devices are enabling communications using a variety of frequencies and applicable coverage areas, such as cellular communications, wireless local area network (WLAN) communications, NFC, etc.
When using NFC, it is desirable for a poller device to be able to detect the proximity of a listener device (e.g., a passive tag, an active device functioning as a passive tag, etc.) using as little power as possible. Power is a particular concern since, in typical applications, the poller device spends most of its time in the listening mode (cycling between listen and sleep with some duty cycle). Another concern is sensitivity of detection, as it is desirable to detect a coupled device at the edge of the operating volume where coupling is weak.
Currently, the poller device may fully activated (TX+RX antennas) for transmission of a carrier signal and listening for a load modulation response. Alternatively, the poller device may activate the TX antenna and monitor the power consumption, and/or the poller device may activate the TX antenna and monitor power consumption over a frequency sweep. In this case, the frequency corresponding to peak power consumption may be used to discriminate proximity of a coupled device. Each of these schemes requires significant power consumption since the full TX antenna and/or both the TX&RX antennas are enabled. Further, even when just the TX antenna is active, the schemes have limited sensitivity as the variation in TX power consumption only provides a weak function of proximity to a coupled device, particularly at the edge of the operating volume.
Thus, improved apparatuses and methods providing mechanisms for detecting a remote NFC device without excessive power consumption may be desired.